Artefact on upper rounded corner of image

loginmen

alt text
I draw alpha background on empty image with rounded corners. After draw small images with CompositionMode_SourceIn, but this do and with images created from fill rect.
I am using qt 6.1.2 and was trying 5.15.2, result are same
code to reproduce

#include <QPainter>
#include <QPainterPath>

void drawAlpha(QImage &image, int width, int height);
void drawSimple(QVector<QImage> &images, QImage &im, int width, int height);
void createImage(QVector<QImage> &images, int width, int height);

int main(int , char **) {
    QVector<QImage> images{};
    createImage(images, 96, 96);
    drawSimple(images, images[0], 220, 285);
    drawSimple(images, images[0], 300, 150);
    images[1].save("../test1.png", "PNG");
    images[2].save("../test2.png", "PNG");
    return 0;
}


void drawAlpha(QImage &image, int width, int height) {
    QPainter paint{ &image };
    paint.setRenderHint(QPainter::Antialiasing);
    paint.setPen(Qt::NoPen);
    paint.fillRect(0, 0, width, height, Qt::transparent);
    QPainterPath path{};
    path.addRoundedRect(0, 0, width,  height, 25, 25);
    paint.fillPath(path, Qt::red);
    paint.end();
}

void drawSimple(QVector<QImage> &images, QImage &im, int width, int height) {
    QImage img{width, height, QImage::Format_RGBA8888};
    drawAlpha(img, width, height);
    QPainter paint{ &img };
    paint.setRenderHint(QPainter::Antialiasing);
    paint.setCompositionMode(QPainter::CompositionMode_SourceIn);
    for (int y = 0; y < height; y += im.height()) {
        for (int x = 0; x < width; x += im.width()) {
            paint.drawImage(x, y, im);
        }
    }
    paint.end();
    images.append(img);
}

void createImage(QVector<QImage> &images, int width, int height) {
    QImage image { width, height, QImage::Format_RGB888 };
    QPainter paint{ &image };
    paint.fillRect(0, 0, image.width(), image.height(), Qt::black);
    paint.end();
    images.append(image);
}

loginmen

helped filling image after creation

img.fill(Qt::transparent);